WO2006128611A1

WO2006128611A1 - Pedal bearing for cycles

Info

Publication number: WO2006128611A1
Application number: PCT/EP2006/004869
Authority: WO
Inventors: Joachim Trommlitz; Lothar Bracht
Original assignee: Aumat Maschinenbau Gmbh
Priority date: 2005-06-01
Filing date: 2006-05-23
Publication date: 2006-12-07
Also published as: EP1728712A1

Abstract

A bottom bracket ball bearing (1) for cycles is presented, having a pedal crankshaft (3), a casing (5) in which the pedal crankshaft (3) is rotatably mounted and in which the pedal crankshaft (3) is secured against axial displacement, a chain pinion (7) with a connection which is fixed in terms of rotation to the pedal bearing shaft (3) in the case of forward rotation by means of the disconnectable coupling (10) in the casing (5) and a freewheeling and overtaking effect when the pedal bearing shaft (3) is stationary or rotating backwards, and having a brake line (14) which leads out of the casing (5) and has a connection which is fixed in terms of rotation to the pedal bearing shaft (3) for backward rotation by means of the disconnectable coupling (16) in the casing (5) and a freewheeling effect of the brake coupling (16) for forward rotation of the pedal bearing shaft (3) and with a rider (18) which is activated by the pedal bearing shaft (3) and alternatively couples the pinion coupling (10), the brake coupling (16) or, in an intermediate position (20), disconnects both couplings (10, 16).

Description

description

Bottom bracket for bicycles

The invention relates to a bottom bracket for bicycles with a pedal crankshaft, a housing in which the pedal crankshaft is rotatably mounted, and in which the pedal crankshaft is secured against axial displacement, and a sprocket with a rotationally fixed connection with the pedal crankshaft.

Bottom bracket of the type mentioned are consistently found in practice.

Furthermore, resignation hubs are known, which are arranged in the rear wheel of the bicycle and which constitute a foot brake for the cyclist. These coaster brakes can not be easily combined with today's usual derailleurs because the front derailleur hinders the use of a Rücktrittnabe obstructive in the way. In unfavorable shift position, the derailleur can be damaged by the chain when using a Rücktrittnabe and continue the derailleur requires a long Winkelweg when receding the pedal. This can cause the effective lever arm of the pedal in the then adjusting brake position of the pedal no longer produces sufficient braking effect, although the cyclist puts all his weight on the pedal.

Therefore, most bicycles sold today have no resignation hub brakes, but there are also hub gears available that can be combined with a resignation hub brake, but the hub gears are inferior to the derailleurs in some respects and therefore lag behind the derailleurs numerically. The hub brake also has a problem with heat dissipation during long runs. This is the desire of many, especially anxious, to people, to fall back on the beloved brake on your back. This gives you a better feeling of safety, especially because there is a fear that the power of the hands might not be sufficient for longer braking maneuvers or the brake levers could not be so easily accessible.

The invention is therefore based on the object to develop a coaster brake, which can be used without compromising on operation and braking effect in derailleurs.

The solution to this problem is given in claim 1. With the solution according to the invention, a bottom bracket is shown, which adds together with known Bowden cables or hydraulic lines to a coaster brake, with their brought out of the bottom bracket brake train on the, in particular chain gears usual rim brakes or on today more and more for the application upcoming disc brakes - can act. In this case, the brake line in addition to the handbrake - z. B. with a brake pad - act on both brake systems, such as the handbrake, so to speak as integral brake. This improves cycling safety because the hands do not always have to be near the handbrake levers. To think about the "bar ends", which allow a different hand and posture, but only with coaster brake allow a prompt braking response.

The invention also opens up the possibility of using the brake train to actuate a hub, disc, or drum brake which is only slightly modifiable in one of the two wheels, in particular in the rear wheel, by means of a push rod or a Bowden cable. With the invention, elements which are known from a Rücktrittnabe, used and divided and adapted in a suitable manner to the bottom bracket and the actual brake, so that a resignation without Utilization of the standard bicycle in the existing chain, starting from the pedal, is possible.

The bottom bracket according to the invention makes it possible to omit the conventional freewheel in the rear wheel. The chain would z. B. while running downhill, but only lead to minimal friction losses in the bottom bracket.

In a preferred embodiment of the invention it is provided that the coupling elements frictionally couple. This allows gentle braking maneuvers and a structurally easier adjustable braking force.

Alternatively, however, also ratchet couplings are provided, as they are well known as a freewheel especially for bicycles. In an advantageous embodiment of the invention, the couplings are designed as cone clutches. This allows a simple design that promises a cost advantage in a highly competitive market.

According to an alternative embodiment of the invention it is provided that the clutches are designed as one-way clutches. These one-way clutches should preferably act frictionally to avoid abrupt braking effects. This embodiment of the invention should also be carried out with ratchet freewheels, as they are common in connection with bicycles. The freewheel clutches have next to the unidirectional freewheel and the opposing entrainment a third shift position, which is designed as idle and in which both in their rotary connection switchable elements can rotate freely in both directions. For this purpose, the each frictionally acting freewheel own clamp body are operated or controlled by the cyclist. In ratchet freewheels, the locking elements or pawls are controlled by the cyclist by the pedal movement. The bottom bracket should include two freewheels in its housing, which have different directions of rotation. The freewheels are arranged coaxially next to one another. In conical design of the clamp body or blocking elements for switching the Idle or the freewheel of one of the input or output side coupling elements with corresponding counter-conical geometry they are to be moved in the axial direction. This represents a combination of cone clutch and freewheel. A particular further developing feature of the invention is the fact that the sprags of the freewheel are driven by the pedal crankshaft. Thus, the control of the freewheel between engage, disengage and the intermediate position simplified. The envisaged by the resignation gears according to the invention in the bottom bracket couplings are designed so that brake elements between the boat and the clutches are otherwise provided.

In the Konen couplings, a structurally simple embodiment of the invention is that both trained as output cones coupling elements are supported in the intermediate position of the shuttle with springs against the boat. These spring elements have the task of establishing a connection between the shuttle and the respective clutch. This ensures that the boat initially does not follow the rotational movement of the bottom bracket, but only then rotates with the bottom bracket shaft when the respective coupling connection is made. Alternatively, spur gears or Stirnmitnehmer on the shuttle and corresponding to the couplings formed projections or depressions are provided, which are in the middle position of the shuttle with two clutches in engagement and with a clutch by traversing the shuttle disengaged before the other clutch engages ,

In a special embodiment of the Konenabstützung is provided that the shuttle is always biased in its axial direction of movement against at least one coupling element. Accordingly, with a form-fitting provisional connection of the shuttle with him opposite cones the shuttle always with at least one coupling element in positive connection.

In a concrete embodiment of the invention it is proposed that the springs are designed as Kurzhubfedern. Kurzhubfedern are z. B. corrugated discs or disc springs.

In order to overcome the shortest possible way when stepping back for braking, the switching path of the shuttle, which must be originally covered by the pedal, must be as short as possible. With the Kurzhubfedern spring strokes can be limited to a few tenths of a millimeter. This allows high forces and spring constants for short strokes.

A preferred embodiment of the invention is to be seen in that on the bottom bracket a screw thread and in the shuttle a corresponding nut thread is formed with a thread pitch at an angle (α) of less than seventeen degrees.

Experiments have shown that at this angle range a sufficient jump start for engaging the clutches is given. It is also advantageous, the pitch angle of the thread in such a way that the threaded connection is not self-locking. In order to optimize the starting aid during engagement, it is proposed to set the friction radii of the springs between the shuttle and outer cone on the one hand and the effective diameter of the thread flanks on the other hand in a ratio of 1, 5: 1 to 2.5: 1, in order to achieve reliable engagement for both the brake and the clutch.

The invention will be explained in detail with reference to the embodiments illustrated in the drawings.

Showing:

Fig. 1: A bottom bracket with cone clutches for driving and braking; Fig. 2: A bottom bracket with one-way clutches for driving and braking;

Fig. 3: A section along line III-III in Figure 2;

Fig. 4: A section along line IV-IV in Fig. 2;

Fig. 5: An enlarged view of a

Brake elements from FIG. 2

In Fig. L, a bottom bracket 1 is shown, which rotatably supports in a housing 5 a pedal crankshaft 3 in rolling bearings 12, 13 and fixed axially. At the ends of the pedal crankshaft 3 truncated pyramidal four-edge 43, 44 are formed, which serve the attachment of pedal arms, not shown, with pedals. The housing 5 is closed with a cover 56 and carries on the cover side a pinion 7, the drive between the pedal crankshaft 3 and the rolling bearing 12 is hollow shaft led out of the housing 5.

The output for the pinion 7 is in addition to the pedal crankshaft 3 and coaxially led out of the housing 5.

In the bottom bracket 5, two separable couplings 10, 16 are added, which are designed as cone clutches and each having a coupling element 21, 23 which is led out of the housing 5 and the drive of the chain pinion 7 or a lever as a radially out of the Housing 5 led out brake cord 14 serve. The simple cone angle is more than 20 angular degrees.

The clutches have the task to transmit the rotational movement of the pedal crankshaft 3 either on the pinion gear 7 or on the brake line 14. The clutches 10, 16 can only alternatively the pinion 7 or led out as a lever from the housing 5 brake train 14, at the free end of a Bowden cable or a brake cylinder can be connected to the pedal crankshaft 3 connect.

The cone clutches 10 and 16 are connected to the pedal crankshaft 3 via a boat 1 8. The boat 1 8 is on one Threaded portion 59 of the pedal crankshaft 3 rotatably and axially displaceably mounted accordingly. The thread of section 59 has a pitch angle α of less than 17 angular degrees. Preferably, the pitch angle is selected so that it is formed between 10 degrees of angle and the friction angle. Depending on the material pairing and lubrication, the friction angle is about 5 degrees. The boat carries in its central bore a corresponding nut thread. The boat 18 is formed as a rotating part, with two outer cones as coupling elements 22, 24 at its longitudinal ends. The coupling element 22 and the coupling element 21 form the separable coupling 10 substantially. The coupling elements 23 and 24 respectively form the coupling 16.

When advancing the pedal crankshaft 3, the coupling elements 21 and 22 of the cone clutch 10 are connected to each other and the Rückwärtsstreten the coupling elements 23, 24 of the clutch 16. When advancing shifts the shuttle 1 8 in the view of FIG. L to the left and forms a clamping connection between the coupling elements 21 and 22 of the clutch 10 and the backward pedaling of the crankshaft 3 shifts the boat 1 8 to the right - in the view of FIG.

In the engaged position of the clutch 10, the pedal crankshaft 3 rotates the pinion 7 without slip. In the engaged position of the clutch 16, in the resignation situation, the shuttle 18 establishes a rotationally fixed connection between the crankshaft 3 and the brake train 14.

In Fig. L the boat 1 8 is shown in an intermediate position 20. In this intermediate position 20, none of the clutches 10, 16 is engaged. This intermediate position 20 is z. Example, when the bicycle is turned off when no action is taken on the pedals, or when the bicycle rolls without drive or brake. Two brakes 41, 57 ensure that both engagement events, that of the clutch 10 and that of the clutch 16, can be initiated. By the braking elements 41 and 57 it is ensured that upon actuation of the Pedals a rotational and axial movement of the shuttle on the threaded portion 59 takes place, with the shuttle 1 8 moves according to the double arrow 60.

These brakes 41 and 57 exert only a small frictional force on the adjacent coupling elements 21, 23, which is only so large that the friction force and the slope force on the threaded portion 59 before the engagement of the clutches 10, 1 6 is overcome. They give the respective coupling process a jump start. The brakes 41 and 57 are arranged in the vicinity of the wall of the housing 5, that is, at a large radius relative to the pedal crankshaft. They are on a peripheral collar of the shuttle 1 8, symmetrically distributed on the circumference, formed. Each brake 41, 57 comprises two nail-shaped brake shoes 88, 89 and 90, 91. The brake shoes are inserted into axial bores of the circumferential collar and the heads of the nails are pressed by corrugated discs 45, 46, 47, 48 against the end faces of the output coupling elements 21, 23.

The brakes 41 and 57 are sized so that the

Brake shoes 88, 90 lift off from the coupling element 21 when the withdrawal comes into engagement, so when the clutch 1 6 is engaged. Conversely, the brake shoes 89, 91 lift off from the end face of the output clutch element 23 when the clutch 10 engages. When driving, there are no friction losses due to the bottom bracket construction according to the invention. The coupling element 23 of the return clutch 16 is slidably mounted on the pedal crankshaft 3. It can also be on its outside in the housing 5, z. B. with a roller bearing, be stored. Finally, the coupling element 23 may also be guided with one or two rolling bearings on the pedal crankshaft 3 in order to reduce the minimal friction occurring during normal driving operation.

Finally, the bicycle can also be pushed back without the resignation intervenes, with no pedal movement takes place and a possible bicycle stand is not blocking the rear-rotating pedal in the way. All common bicycle brakes are resilient in the Open position pressed. This spring force keeps the brake train 14 led out of the bottom bracket housing in the open position of the service brakes of the bicycle (not shown).

In this case, the backward pushing there is on the brakes 41, 57, although slight friction movements, but due to the low friction forces occurring at the brakes 41 and 57 are not perceived by the cyclist. It does not require any additional actions of the cyclist to push back the bicycle or to switch off the coaster brake.

The coupling element 23 for the coaster brake, similar to the coupling element 21, with the omission of the shaft retaining ring 55 and hollow shaft-like led out of the housing 5, whereby the brake train 14 would be executed in approximately mirror-image arrangement to the pinion 7. Alternatively, the coupling element 23 may also be guided and supported in the housing.

The embodiment of the invention shown in Figure 2 operates in the same manner as that of Fig. L, it differs essentially in that the cone clutches are replaced by freewheel clutches 1 1, 1 7.

The bottom bracket 2 of Figure 2 comprises a housing 6, in which a pedal crankshaft 4 in rolling bearings 64, 67 is guided rotatably and secured against axial displacement. Outside of the housing 6 of the bottom bracket 2 engage frame tubes 61 in a known manner. Within the bottom bracket freewheel clutches 1 1 and 17 are provided. With the clutch 1 1, the pinion 8 is connected to the pedal arms 69, 70, at the ends of the pedals 71 are mounted. The freewheel clutch 17 connects the pedal crankshaft 4 with a brake train 1 5, which is led out of a slot-like, extending in the circumferential direction of the bottom bracket 6 at its periphery opening 76 with a seal 62. At this brake line 15, the actual brake system of the bicycle, z. As with rim brakes, in addition to the usually provided manual override on the handlebar of the bicycle via a brake rocker, as described by the Handbrake is known in cars connected. This brake train 15 can also be used to operate a known, easy to be modified hub (resignation) brake.

The two one-way clutches 1 1 (Figure 3) and 17 (Figure 4) are arranged at the longitudinal ends of the housing 6 in its interior. Between the two clutches 1 1, 1 7, a boat 19 is provided, that in response to its and the direction of rotation of the pedal crankshaft, the freewheel 1 1 or the freewheel 17 can grab. The boat 1 9 is rotatably mounted on a threaded portion 72 of the pedal crankshaft 4 and axially displaceable between two axial stops by approximately 1 mm. The slight shift on the pedal crankshaft 4 takes place automatically with the change in the direction of rotation of the pedal crankshaft 4.

The shuttle 19 controls sprags 27, 30 in the clutches 1 1 and 1 7. The shuttle 19 has in the vicinity of its circumference in the axial direction abkragende, engaging in the respective freewheeling, paired fingers 78, 79, which in the manner of a rolling bearing cage determine the position of the clamp body. The clamping bodies are preferably cylindrical, but clamping bodies or balls formed from cylindrical sections can also be used.

By turning the pedal crankshaft 4 in one direction or the other, the freewheels 11, 17 are alternatively brought by the shuttle 19 into their clamping or driving position.

Furthermore, braking elements 42 are provided in each freewheel clutch 1 1, 1 7 as a jump start for clutch operations when engaging. The brake elements are similar and exemplified in Fig.5.

The freewheel clutch 1 1 consists of a trained as a ring gear outer coupling element 25, the clamping body 27, of which three symmetrically arranged copies are shown in Figure 3, and designed as a support disk coupling element 26. In this coupling element 26 are recesses on the circumference arranged in where the clamp body 27 and its controls, which are the fingers 78, 79, are introduced. Trained as a ring gear coupling element 25 forms with its inner circumference one of the two wedge surfaces, in which the clamping body 27 is pressed by the shuttle 19 with his fingers 79. The second wedge surface is formed by the bottom of the recess 92 (FIG. 3) in the coupling element 26 designed as a support wheel.

Trained as a ring gear coupling element 25 carries on its axis of rotation a hub-shaped hollow shaft 63 which is rotatably mounted and axially fixed on the pedal crankshaft 4 and forms a non-rotatable connection 9 with the chain sprocket 8 with a feather key.

In the form of a ring gear coupling element 25, an annular inner groove 68 is provided, in which a not shown spring ring rests, which presses the clamping body 27 in the recesses 92 (Figure 3) in the inner coupling member 26 to control the position thereof.

Trained as a support disk coupling element 26 is mounted on the hub-shaped hollow shaft 63 with a rolling bearing 65.

The brake 42 is - when not shown here - driving operated by the in Fig.2 to the left shifted shuttle. It synchronizes the coupling element 26 designed in the manner of a support disk and the coupling element 25 designed as a ring gear and thus permits the start of the clamping process of the clamping body 27 pressed into the clamping gap.

The two clutches 1 1 and 1 7 act alternatively and in dependence on the direction of rotation of the pedal crankshaft 4. In an intermediate position, not shown, both clutches are separated.

The clutch 17, the recoil clutch is shown in Fig.2 engaged. The boat 19 is in its right position, it rests axially against a collar of the pedal crankshaft 4 and presses with its finger 78, the clamping body 30 in the circumferential direction of the bottom bracket in a nip between an inner clutch member formed as a support member 29 and a ring gear outer coupling element 28. The coupling element 29 designed as a support disk has, like the support disk 26 described for freewheel 11, recesses 93 on its circumference, whose base has one of the two wedge surfaces for the clamping bodies 30, 73, 74 (see FIG ,

A brake 42 brakes and synchronizes the coupling element 29 and the housing 6. For this purpose, the brake 42 is supported against a brake pad 81 on the inside of the end wall of the housing 6. In this position, the finger 78 can press the clamping body 30 into the self-locking clamping gap.

In Figure 3 and Figure 4, this clamping position 77, 80 of the clamping body 30, 73, 74 and 27 is shown in dashed lines. In the situation shown in solid lines, the freewheel is in an intermediate position 95, 20, as it occurs when the bicycle is parked. When driving take the fingers 78 of the shuttle 19, the clamp body 30, 73, 74 and the inner coupling element 29, which is held on the pedal crankshaft with a rolling bearing 66, with. An annular groove 99 shown in Figure 2 is intended for a ring spring, not shown, which presses all the clamping body 30, 73, 74 radially inwardly on the bottom of the recesses 93 and thus avoids unnecessary friction when driving.

In Figure 5, the brake 42 is shown for the coupling element 26 of Figure 2. The brake comprises a slider 82 which is aligned parallel to the bottom bracket and slidably mounted in this direction and carries on its side facing the shuttle 19 a roller 94. The slider 82 is movable in the coupling element 26 in the axial direction and secured against rotation about its longitudinal axis guided in a stepped bore 87 and is resiliently supported against a brake pin 83 from. The turn is supported resiliently against the coupling element 26. Springs 84, 85 are arranged on both sides of a collar 86 on the brake pin 83 within the coupling element 26. With this arrangement it is achieved that a small braking effect is achieved by rolling friction between the shuttle 19 and the slider 82 and the coupling element 26, while between the brake pin 83 and the ring gear 25, a high braking effect is achieved, which formed as a ring gear coupling element 25th and synchronize the coupling element 26 at the beginning of the driving operation (in the clutch 1 1) and hardly hinder the shuttle 19 in its movement.

In this synchronized situation, the shuttle 1 9 with its finger 79 initiate the coupling process on the clutch 1 1.

By formed as corrugated pulleys one behind the other short-stroke springs 84, 85 ensures that only manageable forces between the shuttle 19 and the coupling element 25 can occur and that when switching the shuttle 1 9, the brake pin 83 lifts from the coupling element 25.

Claims

Claims:

1.) Bottom bracket (1, 2) for bicycles

with a bottom bracket shaft (3, 4),

a housing (5, 6),

in which the bottom bracket shaft (3, 4) is rotatably mounted,

- In which the bottom bracket (3, 4) is secured against axial displacement, characterized by

- An output for at least one sprocket (7, 8) in addition to the

Bottom bracket.

- A separable coupling (10, 11) in the housing (5, 6), between the bottom bracket

(3, 4) and the output for the chain sprocket (7, 8)

a brake line (14, 15) which is led out of the housing (5, 6),

- A separable coupling (16, 17) in the housing (5, 6) between the brake line

(14, 15) and the bottom bracket (3, 4) and

- A through the bottom bracket (3, 4) operated Schiffchen (18, 19), the alternative

- the pinion clutch (10, 11) switches,

- The brake coupling (16, 17) switches or

- In an intermediate position (20, 45), both clutches (10, 11, 16, 17) separates.

2. bottom bracket (1, 2) according to claim 1, characterized in that the coupling elements (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 73, 74) frictionally couple.

3. bottom bracket (1, 2) according to claim 1, characterized in that the couplings are designed as cone clutches (10, 16).

4. bottom bracket (1, 2) according to claim 1 or 2, characterized in that the clutches are designed as one-way clutches (11, 17).

5. bottom bracket (1, 2) according to claim 4, characterized in that the clamping body (27, 30, 73, 74) of the bottom bracket (4) are driven.

6. bottom bracket (1, 2) according to one of the preceding claims, characterized in that braking elements (41, 42) between the shuttle (18, 19) and the clutches (10, 16, 11, 17) are otherwise provided.

7. bottom bracket (1) according to claim 2, characterized in that both as output cones formed coupling elements (21, 23) in the intermediate position (20) of the shuttle (18) with springs (46, 47) are supported against the shuttle (18) ,

8. bottom bracket (1) according to claim 3, characterized in that the shuttle (18) in its axial movement direction is always biased against at least one coupling element (21, 23).

9. bottom bracket (1, 2) according to claim 8 or 9, characterized in that the springs (45, 46, 84, 85) are designed as Kurzhubfedern.

10. bottom bracket (1, 2) according to one of the preceding claims, characterized in that on the bottom bracket shaft, a screw thread and in the shuttle a corresponding female thread is formed with a thread pitch of less than seventeen degrees.